


couldn't get enough (so i had to self-destruct)

by oryx



Category: Kamen Rider Build
Genre: Barebacking, Biting, M/M, Possessive Behavior, Threesome - M/M/M, Unhealthy Relationships
Language: English
Status: Completed
Published: 2018-04-07
Updated: 2018-04-07
Packaged: 2019-04-19 22:00:41
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,805
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/14246637
Author URL: https://archiveofourown.org/users/oryx/pseuds/oryx
Summary: The adventures of Kiryu Sento, professional mediator.





	couldn't get enough (so i had to self-destruct)

**Author's Note:**

> ... well here we are again folks. no excuses for this and i'm very sorry.  
>  set before the vs seito proxy battle for anyone who cares about things like canon timelines irt the filth they read

  
It’s nearing one in the morning when the screen of the Build Phone lights up with the incoming message.  
   
_meet at the eros room 204 in 30 mins? important war business ;) ;)_  
   
Sento stares down at the words with the throb of a headache already beginning to form between his eyes.  
   
He should absolutely positively set his phone aside right now and forget about it. He should finish running these last few tests and go to bed, and wake up in the morning without any feelings of bitter regret lying in the back of his throat.  
   
And yet it’s never that simple. He’d love to just delete that number from his contacts altogether, but that’s far beyond the realm of possibility at the moment. Information is the most precious resource in any war, after all.  
   
You don’t just give up a wellspring, no matter how dangerous the banks around it might be.  
   
(Or something like that. He’s never been much for metaphor.)  
   
He’s grateful at least that it’s late. Misora and Ryuga are both asleep, and so there’s no one to question him as he leaves, ascending the staircase and closing the refrigerator behind him as quietly as he can, tiptoeing across the wooden floorboards of the café. He shivers against the brisk chill of the night air as he steps out the door, already wishing he’d thought to grab a jacket.  
   
It’s almost silent in the city. The nights have been this way, since the war began, without much of the low, steady hum of activity they used to have. Nowadays there are only sirens, sometimes, or the distant whir of helicopters overhead to cut a swath through the quiet. It’s eerie, and it sets his teeth on edge, and he quickens his pace as he walks through the dark streets.  
   
Countless businesses have shut their doors, too. The hotels, certainly. But while the respectable hotels have all been turned into shelters for displaced citizens, or meeting halls for public safety committees, there are a few less reputable establishments that have been left simply empty.  
   
Hotel Eros, for one, and Sento stands in front of it with a grimace tugging at his mouth. Its neon sign – the ‘o’ in the shape of a heart – is unlit, of course, but he can almost imagine the lurid pink glow. The owners have yet to come back to put away the billboards outside the place advertising its wide selection of themed rooms, including one covered floor-to-ceiling in mirrors. He hopes to god that’s not room 204.  
   
The interior smells a bit musty after sitting mostly unoccupied for weeks now, and that combined with the dimness – the dark red walls and carpeting seeming to mute what light there is – creates a rather suffocating atmosphere. He feels somehow both tired and wound tight with unease as he makes up the stairs and comes to stand outside the door of room 204, taking a deep, steadying breath before pushing his way inside.  
   
Blessedly, the room is almost indistinguishable from an average hotel suite, just with slightly tackier furniture and mood lighting and an overall aura of cheap sleaziness. Isurugi glances up from his phone, eyes brightening, and waves to him from where he’s sitting on the edge of the bed. Sento scowls in return, and is about to question his terrible taste in meetup locales when his eyes are drawn to the corner of the room.  
   
To Himuro Gentoku lounging against the wall and staring moodily through a gap in the blinds.  
   
Sento stops. He glances back and forth between the two of them for a moment, finally managing to point in Gentoku’s direction while leveling Isurugi with an accusing look.  
   
“What is  _he_  doing here?”  
   
Isurugi raises an eyebrow. “He’s a player in all this, too, you know. It can’t be that much of a surprise that he’d show up to one of our little meetings.” A pause, contemplative as he uncrosses his legs and gets to his feet in a single fluid motion. “Although, if I’m being totally honest, I may have… stretched the truth just a smidge with that ‘important war business’ bit. Really, we were just hoping that you could settle a dispute for us.”  
   
Sento stares at him blankly.  
   
“I’m leaving,” he says finally, monotone, turning back towards the door with a feeling of bone-deep weariness pulling at him. No sooner has he gotten a hand around the doorknob than Isurugi is suddenly, alarmingly close, reaching past him to slam the door shut again. Sento swallows hard, glancing over his shoulder to find him smiling in that way that must look so pleasant to the untrained eye.  
   
“C’mon, not so fast,” he laughs. “You came all the way over here just to leave? At least hear us out. It’s for your benefit, too.”  
   
He’s putting his hands on Sento’s shoulders and forcibly turning him around before he has time to protest, pushing him back into the center of the room.  
   
“You may have noticed,” he says, “that Himuro-kun refuses to call you anything but ‘Katsuragi.’”  
   
Gentoku’s lip curls, derisive, looking over at them for the first time since Sento came in. “Because that’s his name,” he says.  
   
Isurugi sighs, and Sento can feel it against the back of his neck. “That  _used_  to be his name. See, Sento, this is our dilemma. He thinks that just because you’ve got Katsuragi’s smarts,” and here his hand leaves Sento’s shoulder to rest instead against the crown of his head, fingers curling very slightly against his scalp in a way that makes his skin prickle, “that his memories must still be rattling around up here, too, somewhere. But of course I keep telling him it’s no use. That you’re someone else entirely, now.”  
   
Sento forces himself to knock his hand aside and step away. “Why do  _you_  care what he thinks about me?”  
   
Isurugi gives him one of those mock-affronted looks. “What do you mean, why? I put a lot of time and effort into you, you know. I always thought the name was pretty clever. Not to mention all the other work that went into creating ‘Kiryu Sento.’ It’s hurtful, that he won’t even acknowledge something I’m rather proud of.”  
   
Sento’s throbbing headache from earlier is beginning to return full-force. “…You’ve got to be kidding me,” he mutters, massaging his temples tiredly.  
   
Out of the corner of his eye he can see Gentoku bare his teeth in an almost joyless smile. “See? Katsuragi agrees with me. Your little ‘creation’ is just a flimsy cover. If his memories were truly gone, he wouldn’t still have his intellect, would he? He’ll remember the rest soon enough. And when Faust returns we’ll destroy you first, Isurugi. You can count on that.”  
   
Isurugi looks rather unimpressed by this threat. “When Faust returns, huh?” He tilts his head to the side, humming thoughtfully. “Y’know, Himuro-kun, I’ve been wondering… Did Katsuragi ever actually  _like_  you? Because I’m really getting the sense you might’ve been far more enamored with him than he was with you.”  
   
At this, something hot and angry flares to life in Gentoku’s eyes. He moves across the room so that the two of them are face-to-face, drawing himself up to full height. “We were partners,” he growls. “We shared ideals. Which is something you wouldn’t understand, would you?”  
   
Isurugi presses a hand against his heart, pretending to wince. “Ooh, so harsh. There’s no need to – ”  
   
Before he can even really think it through, Sento finds himself stepping in between them.  
   
“Would both of you please  _shut up_ ,” he hisses. There’s a muscle beneath his eye twitching and his jaw hurts from clenching it and he can’t listen to this any longer. He rounds on Gentoku first, brandishing a finger in his face. “You – I don’t know what I used to be to you, but I’m not that person anymore. I’m taking responsibility for the things I did back then. But that’s it. I don’t remember any of it, and at this point… I don’t think I ever will. So just – forget it, will you? I’m not going to just wake up one day and be him again.  
   
“And  _you_ ,” here he turns on his heel to glower at Isurugi, “had better quit talking about me like I belong to you. You’re responsible for part of me but definitely not all of me, and you know it as well as I do. I have my own life. And it just so happens that I like this name. But not because  _you_  gave it to me. Neither of you ‘wins’ this stupid argument, alright? And I’d prefer if you kept me out of these things in the future.”  
   
He breathes heavily in the silence left behind, some of the angry tension beginning to leave him little by little, like a coil of wire being unwound. Isurugi blinks at him, wide-eyed.  
   
“Wow,” he murmurs. “Very impassioned. And,” here he lifts his hands as if to say  _what can you do_ , “I guess that’s about the answer I expected. Though I don’t know if it’s gonna cut it with our oh-so-serious friend here.”  
   
Sento turns back to look at Gentoku, whose eyes seem darker than usual, somehow, his mouth set in a thin line. “…That’s not good enough,” he says, low and biting. He’s reaching out before Sento can react, pressing his palms against Sento’s throat, along the line of his jaw, holding his face in his hands in a way that feels far too intimate. “ _You have to remember_ ,” he says, leaning in, and this time his voice is insistent (pleading, almost, but maybe that’s just his imagination). “I know you will. Remember Faust, remember me, remember what we were trying to create for this country – ”  
   
Pulse pounding, Sento is stumbling backwards to pull away from him a second later, forgetting the position he’d unwisely put himself in. He freezes when he feels his back hit Isurugi’s chest.  
   
“You seem a little desperate, Himuro-kun,” Isurugi says. “Almost like you’ve realized you’ve already lost this one.” Sento tenses up even further as Isurugi slides an arm around his shoulders, the other curling around his waist, fingers sliding beneath the hem of his sweater. “I mean. We both know you never got very far with your beloved Katsuragi. It was just you and your fantasies, wasn’t it? Whereas…”  
   
He trails off in a suggestive manner.  
   
Gentoku’s shock morphs into a kind of sneering disgust a moment later. “You can’t be serious,” he says slowly, meeting Sento’s eyes. At his side, his hand is curling into a white-knuckled fist. “You and him?”  
   
Sento grits out a sigh. It’s not like he’s proud of it. These things just keep happening somehow. “Can you not bring that up like it’s some weird competition?” he snaps at Isurugi. “What even  _is_  the debate at this point? Who can be the most creepy and entitled?”  
   
Isurugi’s laugh is warm against the slope of his shoulder.  
   
“See? It’s that attitude that I can’t get enough of. Himuro-kun, let’s be real. Katsuragi would never have been this much fun.”  
   
“Don’t pretend like you knew him like I did,” Gentoku snarls, but there was a beat of hesitation before he spoke all the same.  
   
“Well, I guess you’ve got a point there,” Isurugi muses. “You’re probably never really going to listen to me, are you? But maybe…” His fingers, splayed against the flat of Sento’s stomach, trail lower, slipping beneath the waistline of his jeans (when did he unbutton them? he doesn’t even remember), and Sento can’t help the small, startled noise that escapes him. “I’d be willing to let you have a turn, you know.”  
   
Gentoku’s eyes narrow as Sento grinds his teeth together.  
   
“What did I literally  _just_  tell you?” he asks, each word taut with irritation. “About acting like you own me?”  
   
“Hm? You like it, though, don’t you?”  
   
“That’s – ” Sento stops. He opens his mouth, expecting some kind of obvious retort to occur to him, and then closes it again wordlessly. A chill travels down his spine as he considers this. Does he?  
   
“What are you on about?” Gentoku is asking, suspicion written across his face.  
   
“I’m just saying,” Isurugi continues, “that it might be the perfect way to come to an agreement here. A little bit of… physical closeness could help you accept the truth, I think. And if not, well.” Sento can feel him smiling. “Then you’ll finally have gotten to touch Katsuragi the way you always wanted to.”  
   
Gentoku seems to ponder this. He tilts his head, raking his eyes over Sento with an odd glint there, like he’s only now seeing him for the first time, and it feels, then, as if the air in the room has shifted, far heavier and closer than it had been just a second ago. Sento licks his lips nervously.  
   
“So, what?” he asks, his voice faltering a bit. “Do I not get a say in this?”  
   
“Oh, by all means, make your choice,” Isurugi says, sounding a bit like he’s biting back another laugh. His thumb brushes along the curve of his hipbone, and Sento takes a sharp breath.  
   
Well, he thinks. It’s not as if he hadn’t been expecting this sort of outcome tonight.  
   
Just. Maybe not  _exactly_  this.  
   
  
   
  
   
Gentoku runs a thumb along his jawline, a kind of keen interest in his eyes, and yet it’s not Isurugi’s fingers he’s watching – two of them, now, pressed deep inside Sento and stretching him open little by little, Sento’s spread legs already trembling from it as he lets his head fall back against Isurugi’s shoulder.  
   
Instead, Gentoku is staring straight at Sento’s face. Even as he forces himself to look away, up at the chintzy patterned ceiling, he can still feel the weight of it lingering. It seems to sink down beneath his skin and turn into liquid heat, just as much as the curve of Isurugi’s fingers, going right to his stiffening cock.  
   
Isurugi works a third finger inside him and Sento’s grip on his fistful of bed covers tightens, twisting the fabric in his hand.  
   
“You know you don’t have to just watch, Himuro-kun,” Isurugi says amusedly. Sento can feel it as much as hear it – the hum of the words in Isurugi’s chest where it’s pressed against his back.  
   
When Gentoku doesn’t grace him with a reply he huffs out an exasperated sigh, twisting his fingers in such a way that Sento’s breath gets caught in the back of his throat, lips parting without a sound.  
   
Still watching his face, Gentoku’s hand strays to the zipper of his pants.  
   
His cock – not long, but thick – is already hard as he takes himself in hand and strokes himself idly. There’s something about the assuredness of it – him standing there still fully clothed, tugging at his cock with lazy strokes – that makes Sento feel oddly dizzy. He almost thinks that Gentoku  _might_  be content to just watch, but then he’s stepping closer, reaching out to put a hand on Sento’s inner thigh, the calluses on his palm rough against the soft skin there.  
   
“There you go,” Isurugi says, a smile in his voice. He takes his fingers away with a slick noise and Sento can’t help but the small whine of protest that escapes him. “Isn’t this downright heartwarming? Himuro-kun finally getting to act on his feelings. You’re lucky I was in such a generous mood today.”  
   
Sento sucks in a breath at those words, something low and dark twisting in the pit of his stomach. Gentoku, on the other hand, doesn’t even seem to hear.  
   
“Katsuragi,” he breathes. His eyes are alight with an emotion Sento has never seen on his face before as he leans down to mouth at his neck. His beard scratches against his skin and Sento almost laughs, before he feels Gentoku’s teeth as well, his tongue, and that sound gets abruptly cut off.  
   
“You always wanted this, too, didn’t you?” Gentoku murmurs. “You told me ‘no’ that night, but I knew… I knew you didn’t really mean it.”  
   
Sento feels somewhat lightheaded. He doesn’t remember. He’s sure he never will. And yet somehow in this moment he feels as if he could – like that memory is trying to claw its way up from somewhere dark.  
   
Isurugi is shifting behind him and he’s being pushed on to his back before he can truly come to terms with the situation, his head ending up in Isurugi’s lap, Gentoku above him with his mouth hot against his collarbone, his fingers digging into his hip where he’s holding him tight enough to bruise.  
   
The head of his cock presses against Sento’s entrance, and he only tenses for a moment before relaxing into it. (Maybe it’s the sensation of Isurugi’s hand in his hair, twining strands between his fingers and tugging lightly.) He takes a choked breath as Gentoku fucks into him with aggressive suddenness, making a low, desperate sound in the back of his throat. The screaming stretch of those muscles, the heat of his cock inside him overwhelming, and Sento’s eyes flutter shut for a moment. When he opens them again Isurugi is peering down at him with an expression of mild interest.  
   
“Well?” he prompts. “Is this beautiful connection bringing anything to the surface? Your old feelings for Himuro-kun that I’m sure you definitely had?”  
   
Sento is unable to answer as Gentoku pulls back before thrusting in deep, hitting that spot that makes him feel like someone just threw a veil of hazy warmth over his thoughts.  
   
“You,” Gentoku growls, his breath coming a little quick, a faint flush in his cheeks, “just hate the idea that someone might find out, don’t you? That you’re not as powerful as you claim to be.”  
   
Isurugi shakes his head with a quiet laugh. Sento stares up at them, at the fact that neither of them are paying him any mind in this moment, as if he were nothing more than a toy, and beneath his irritation at this there is something else, too, something that makes his cock twitch against his thigh.  
   
“You can believe whatever you like,” Isurugi says, shrugging a shoulder. His hand strays from Sento’s hair and drifts down, fingertips tracing the outline of his lips before slipping inside, Sento opening his mouth obediently before realizing what he’s doing. They press against his tongue lightly in a way that sends a thrill through him. “The fact of the matter is, I was always going to win this one, Gentoku. Katsuragi or not, do you really think he would’ve spread his legs just for you?”  
   
Gentoku’s eyes are like two chips of flint as he returns his gaze to Sento, to his lips parted to allow Isurugi’s fingers, and Sento wonders, distantly, what he must look like right now. Wrecked, undoubtedly. Gentoku’s expression darkens further and he leans down again, this time to sink his teeth into Sento’s shoulder hard enough to draw a gasp out of him. Painful, and yet. Against all good judgment he ends up reaching up to palm the back of Gentoku’s neck, dragging him closer still, Gentoku burying his cock up to the hilt inside him as he licks and sucks blood to the surface like he’s trying to leave a lasting mark.  
   
Despite it all, it’s looking up to see Isurugi smiling down at him, feeling his thumb caressing his bottom lip, that sets Sento over the edge, curling his fingers in Gentoku’s hair as it hits him, seeing white around the edges of his vision, his own come spilling across his stomach. It takes Gentoku only a few more thrusts to come as well, hot inside him, spilling out as he pulls free and dripping down the curve of his ass.  
   
He should get angry about that, shouldn’t he. He should…  
   
But the tiredness is overwhelming in the aftermath, the sluggish malaise that always follows this coupled with the realization that it’s two in the morning and he hasn’t slept in well over thirty-six hours. All he can really bring himself to do is lie there, feeling distant from himself, his skin still buzzing with a sort of fading hum.  
   
Gentoku doesn’t look at him as he gets up and walks away. The bite mark on his shoulder is already beginning to sting, and Isurugi touches the edges of it with a wry amusement in his eyes.  
   
“How very like him,” he says. His other hand drifts back to twine in Sento’s hair again, combing through it in a manner that’s almost sickeningly gentle. “He really doesn’t hold back, does he?”  
   
“You’re no better,” Sento mutters. “Just… in a different way.”  
   
“Oh, come on,” Isurugi says, pouting down at him. “That’s not being very fair! You know what I think, Sento?” And here his expression turns contemplative and sly, a pleased sort of glint in his eyes. “I think you’ll come to appreciate my methods before the end.”  
   
“…So you keep telling me,” Sento says dryly, and closes his eyes (just to rest them for a moment, nothing more), the palm of Isurugi’s hand still warm and firm against his temple, like a weight that’s pinning him in place.  
   
  
   
  
   
  
He wakes, light streaming in through the window, with his entire body feeling like one large ache, his own come dry on his stomach and Gentoku’s an unpleasant reminder between his thighs. He drags a hand down his face and fumbles around for his phone to find seven new worried messages from Misora, Ryuga, and Sawa wondering where he is, and simply stares at them groggily for a time before shutting it off again. He’ll come up with an excuse later. (He’s been getting good at those, lately.)  
   
He turns his head to see another message waiting for him on the nightstand – a scrawled note, the handwriting unfortunately familiar.  
   
_If you’d believe it, the water is actually still on for this place if you want to get a shower. Lucky you, right? :)_  
   
_I’ll message you again soon when I have some important intel for you~ Maybe next time I’ll invite Utsumi along – he’s pretty well-informed, too. And he’s been a big help lately. I think he deserves a spot at one of our meetings. xoxo_  
   
Sento scowls at the note, crumpling it in his hand.  
   
As if he’s going to be accepting any more of these ridiculous rendezvous, knowing full well that it could turn into some kind of love hotel council of suspicious individuals.  _He’ll_  be the one setting the terms for their meetings from now one. He’s not interested in an extended repeat of last night.  
   
Sento hesitates; uncrumples the note and stares at it for a time before shaking his head and tossing it aside, an uncomfortable feeling wound tight in his chest.  
   
Definitely not.


End file.
